In recent years, a substrate storage container of a front box open type is manufactured and sold along with an increase in the diameter of substrates represented by semiconductor wafer substrates, photomask glasses, and aluminum disks. The substrate storage container mainly includes: a front-open container body for aligning and storing a plurality of substrates; and a lid removable to open and close an open front surface of the container body. The substrates stored in the substrate storage container are supported one by one by holding portions formed in the container. In general, the container body and the lid are formed from a polycarbonate resin or a polypropylene resin with an excellent rigidity, an excellent visibility of the inside of the container from the outside, and a high cleanliness.
The substrates rotate in the container in some cases due to vibration or impact on the substrate storage container. When the substrates rotate in the container, friction between the substrates and grooves of the holding portions may generate abrasion powder, and this increases the risk of contamination of the substrates. To reduce the risk, holding portions included in a well-known substrate storage container are formed by a material with a frictional resistance smaller than a container body and a lid and with a sliding property more excellent than the container body and the lid. A high wear resistance polycarbonate resin or polybutylene terephthalate resin containing a sliding material is used as the material (for example, see Patent Literature 1). Furthermore, applying a polybutylene terephthalate resin over surfaces of holding portions made of a polycarbonate resin is also proposed (for example, see Patent Literature 2).